Both dragonflies and damselflies belong to the ancient order,
Odonata (toothed ones). Within this order are two distinct
sub-orders; Anisoptera, the dragonflies and Zygoptera, the
damselflies. These are easily distinguished from each other in
numerous ways. In dragonflies, except clubtails, the eyes meet or
nearly meet in the middle of the head, whereas damselflies have
widely separated eyes. Dragonflies, when perched, hold their wings
horizontally while damselflies fold them over their backs. Both can
move their wings independently of each other giving them greater
control in flight, though dragonflies have strong, sustained flight
and damselflies are more weak and fluttery. Also, damselflies are
smaller and more slender than their more robust cousins.

Both dragonflies and damselflies have formidable mandibles for
eating any insect they can catch with their legs, from mosquitoes to
beetles to other odonates. Their compound eyes, along with three
little ocelli or simple eyes allow them to see in almost 360 degrees.
Scientists believe that 80% of the odonate brain is used for visual
information. Hence, the difficulty in netting them and their 98%
catch rate.

Sex is both unique and challenging for these insects. Claspers at
the end of the males, though slightly different in both dragonflies
and damselflies, serve the same purpose, to catch and hold the
female. The sexual genitals in both genders are uniquely designed to
act as a lock and key. Though some males will try to breed outside
their species, it is invariably doomed to failure. They just don’t
fit.

Unlike butterflies that go through a four stage metamorphosis,
dragonflies and damselflies go through a three stage, incomplete
metamorphosis: egg, larva and adult dragonfly. Most of its life is
spent as a voracious nymph hunting underwater in streams, lakes and
ponds. As the nymph grows it sheds its skin numerous times (instars).
The nymph stage, depending on species and location can last from a
few months to 8 years, though in most North American species, only
from one season to the next. Just before its last instar, the nymph
goes into diapause or a rest period where the last changes in its
body, such as the wings, are completed. It then crawls out onto the
stem of a plant or onto a rock or tree trunk and completes its life
cycle by freeing its now tranformed adult body from the old nymph
skin. After hardening its wings with hemolymph (blood) and letting
them dry, the teneral dragonfly or damselfy flies off and begins its
new life as an adult.